1. Field of the Invention
The present invention relates to a pedometer for detecting vibrations in the stepping direction, in particular to a pedometer that can directly detect vibrations of a jogger""s body with a detector positioned orthogonal to the moving direction.
2. Description of Related Arts
Pace counting devices can be classified into mechanical and electronic types. With reference to FIG. 7, the structure of a mechanical type pedometer includes a shell (50), a swing arm (51) being installed inside the shell (50) for normal operation in the upright position, a spring (52) and a weight (53) being attached to the end of the swing arm (51), an electronic switch (54) being disposed to correspond with the position of the weight (53); and a counting circuit (55) being connected to the electronic switch (54).
When in motion, the jogger""s feet pound the ground exerting a downward force. Since the swing arm (51) is positioned perpendicular to the horizontal plane, the downward force will pull down the weight (53) to touch the electronic switch (54), thus the electronic switch (54) is toggled by the footsteps. The counting circuit (55) thereafter detects the status change in the electronic switch (54), and then increases the count by one. Therefore, the pace count will continue until when the jogger stops moving. The counting circuit (55) working in conjunction with the electronic switch (54) and the swing arm (51) records the actual footsteps of the jogger. However, this kind of mechanical pedometer is known to have weaknesses, such as too much noise disturbance, oxidation of the contact points, and metal exhaustion of the spring. In addition, since the device is inherently designed for upright mounting, only directly downward vibrations can toggle the electronic switch (54) in the counter to produce the pace count, whereby false readings may occur if the vibration is oblique to the switch. Such false readings will be very confusing and probably infuriating to the jogger as obviously such a person has a particular interest in knowing the precise distance traveled.
In order to overcome the weaknesses mentioned above, electronic pedometers having higher precision have recently been developed. The physical structure of a typical electronic type pedometer is illustrated in FIG. 8, including a shell (60), a ceramic piezoelectric component (61) being installed laterally inside the shell (60), and a counting circuit (62) being connected to the ceramic piezoelectric component (61).
The above ceramic piezoelectric component (61) detects substantial downward force generated by walking, jogging etc, and converts the downward force into a signal output to the counting circuit (62) for pace counting.
The use of the ceramic piezoelectric component (61) to detect downward vibration can eliminate the problems associated with the swing arm (51) in a mechanical pedometer. Since the ceramic piezoelectric component (61) is designed to detect downward force exerted by motion, the counting circuit (62) has to be mounted laterally inside the counter shell (50) which is secured onto the jogger in order to take the pace count with accuracy.
Some manufacturers have tried to increase the length of ceramic piezoelectric component (61) to increase the efficiency of the pedometer, while keeping the slim shape of a portable pedometer. Others have tried to increase the payload to increase the sensitivity of the pedometer, but this kind of modification also magnifies after shocks following each foot step, which often causes the counting circuit to pick up after shock signals resulting in counting errors.
From the above discussion of these two types of pedometers, it is apparent that the conventional vibration detector has to rely on more substantial downward force generated by footsteps to maintain an accurate counting. Furthermore, the jogger has to preset the direction parameter of the counting device telling the counting device which direction the jogger is going to take; otherwise, some of the counting devices may record incorrect pace counts. To correct this problem, some manufacturers of pedometers have come up with new pedometers claiming that the new counters do not need presetting of the stepping direction, and the size of these counters is small enough to be carried along in a pocket. However, in reality, if the stepping direction is not preset, the pace counting by these portable devices is not very reliable.
To satisfy the need for a direction-less pedometer, the pedometer has to use two vibration detectors orthogonally disposed to each other to detect vibrations from every direction, such that the counter can be rotated angles without affecting the operation results. Looking at the current market situation, pedometers with such capabilities usually have a large physical size and are relatively expensive.
The main object of the present invention is to provide a pedometer that can detect body vibrations in the motion direction, and can still be operated accurately after changing the counter position.
Such a pedometer is fully portable and uses a single detector for detecting body vibration. Other advantages of the new pedometer are that it can directly detect body vibrations in the direction of motion, and the new counter is less affected by after shocks as compared with conventional pedometers. Using a piezoelectric element, the new pedometer is able to directly detect body vibrations in the motion direction with good accuracy.
To this end, the physical structure of the pedometer comprises:
a main body;
a vibration detector being laterally installed inside the main body; and
a counting circuit also being laterally installed inside the main body, which is formed by a signal amplifier circuit and a signal detection circuit.
The present invention is characterized in that the pedometer having an orthogonal vibration detector is able to detect body vibrations generated by a jogger in the direction of motion. Furthermore, the new pedometer has a signal amplifier circuit built in for amplifying weak vibration signals in a certain direction if the vibration detector is moved to a different position other than the orthogonal position.
The present invention is also characterized in that a single vibration detector is used in the pedometer. With proper positioning of the vibration detector orthogonal to the direction of motion and the sophisticated control logic in the counting circuit, the new pedometer is able to take accurate count of the jogger""s pace without having to use two orthogonal vibration counters.
The features and structure of the present invention will be more clearly understood when taken in conjunction with the accompanying drawings.